In Photos: Swimming robot probes Fukushima reactor to find melted fuel

This image taken by the robot shows the inside of the containment vessel of the No. 3 reactor at its Fukushima No. 1 Nuclear Power Plant on July 19, 2017. Some structures are seen inside the water-filled vessel. (Photo courtesy of the International Research Institute for Nuclear Decommissioning)

This image taken by the robot shows the inside of the containment vessel of the No. 3 reactor at its Fukushima No. 1 Nuclear Power Plant on July 19, 2017. Some structures are seen inside the water-filled vessel. (Photo courtesy of the International Research Institute for Nuclear Decommissioning)

This image taken by the robot shows the inside of the containment vessel of the No. 3 reactor at its Fukushima No. 1 Nuclear Power Plant on July 19, 2017. Some structures are seen inside the water-filled vessel. (Photo courtesy of the International Research Institute for Nuclear Decommissioning)

This image taken by the robot shows the inside of the containment vessel of the No. 3 reactor at its Fukushima No. 1 Nuclear Power Plant on July 19, 2017. Some structures are seen inside the water-filled vessel. (Photo courtesy of the International Research Institute for Nuclear Decommissioning)

This image taken by the robot shows the inside of the containment vessel of the No. 3 reactor at its Fukushima No. 1 Nuclear Power Plant on July 19, 2017. Some structures are seen inside the water-filled vessel. (Photo courtesy of the International Research Institute for Nuclear Decommissioning)

This image taken by the robot shows the inside of the containment vessel of the No. 3 reactor at its Fukushima No. 1 Nuclear Power Plant on July 19, 2017. Some structures are seen inside the water-filled vessel. (Photo courtesy of the International Research Institute for Nuclear Decommissioning)